The following is an example of method of manufacturing a liquid crystal display device. Switching elements (e.g., TFT) and pixel electrodes are arranged on one of glass substrates provided in a pair, and counter electrodes are arranged on the other glass substrate. Those glass substrates are then bonded with spacers between them. Liquid crystal is disposed between the glass substrates so as to form a liquid crystal layer. Then, polarizing plates are attached to respective surfaces of the glass substrates to produce a liquid crystal panel. A lighting device that has a plurality of cold cathode tubes as light source is mounted to the liquid crystal panel.
In such a production process of liquid crystal display device, a display defect detection may be performed after a liquid crystal layer is formed, for example. In such an inspection process, if a foreign substance is present in the liquid crystal layer, light that strikes it is irregularly reflected and may create bright dots on black display. These dots would be detected as luminance point defects. The luminance point defects are very noticeable. Therefore, they greatly degrade the display quality and yield in production.
Patent Document 1 discloses an example of method of compensating for such a luminance point. If a luminance point defect is present in a pixel element, a processed concave portion is formed near a surface of transparent substrate on an incidence side of a travel path of light that illuminates the pixel element. The concave portion has a rough bottom surface for light scattering.
According to the invention of Patent Document 1, illumination light is scattered by the processed concave portion, which is formed on the transparent substrate on an incidence side, and therefore the luminance point picture element is not noticeable with respect to normal picture elements in the surrounding area.
Furthermore, as a method of compensating for a luminance point defect by making it invisible, means for compensating for a luminance point defect by blackening that makes a luminance point defect occurrence area black for normally black display is used (e.g., Patent Document 2). A black dot on the display surface created by blackening is less noticeable compared to the luminance point and therefore it does not lead to significant degradation of display quality. Thus, yield in production can be improved.    Patent Document 1: JP-A-06-313881    Patent Document 2: JP-A-2005-189360